The purpose of this proposal is to clarify the pattern of care provided to patients with chronic kidney disease and elevated cardiac troponin (cTn) in the clinical context of acute coronary syndrome (ACS). Chronic kidney disease (CKD) is a well known risk factor of cardiovascular mortality and morbidity. Cardiac Troponin (cTn) are highly sensitive and specific markers for the diagnosis of myocardial injury and infarction and for risk-stratification of ACS. As such, the measurement of cTn has been integrated as a tool for the diagnosis of acute myocardial infarction. Whether patients have decreased kidney function or not, the decision making process is easy when those admitted in the emergency room for ACS suspicion have clear ST segment elevation on the ECG, or have high cTn. However, for many physicians, the path is less clear if patients do not have any ST elevation, have slightly elevated cTn (between 0.03 and 0.1) and have decreased kidney function. We propose to examine the pattern of care provided to patients admitted to the emergency department for suspicion of ACS, according to their kidney function and cTn level. This study will be a retrospective analysis of patients with documented cTnT admitted to the Christiana Care Health System since 2004. We will restrict our dataset to the patients who do not have an ST-elevation MI. This study will allow us, not only to clarify the current decision making process faced by physicians who take care of patients with decreased kidney function in the context of an ACS but also to provide data for refining the guidelines according to cTn levels and kidney function. The specific aims are as follows: Aim 1: For each cTn levels, compare the pattern of care provided to patients with normal kidney function to that of patients with decreased kidney function. Aim 2: For each cTn levels, examine the independent association between type of treatment (invasive versus conservative) and CKD stages, after adjusting for comorbidities, burden of disease, severity of coronary disease and insurance status. Aim 3: At each level of cTn, identify the determinants of in hospital major cardiovascular events including mortality, in patients with decreased kidney function for each stage of CKD. PUBLIC HEALTH RELEVANCE: Because clinical trials always exclude patients with decreased kidney function, the management and care of these patients is not based on clear evidence although the prevalence of CKD in patients with ACS is very high (more than 60% from our preliminary data) and is likely to increase as the population ages. This study will provide data to clarify the guidelines and improve the management of these patients.